Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 26, 2020	Dec. 26, 2019
Accounts receivable, reserves	$ 998	$ 762
Preferred Stock, par (in dollars per share)	$ 1	$ 1
Preferred Stock, authorized	1,000,000	1,000,000
Preferred Stock, issued	0	0
Cost of Common Stock in treasury, shares	133,363	242,853
Common Stock [Member]
Common Stock, par (in dollars per share)	$ 1	$ 1
Common Stock, authorized	50,000,000	50,000,000
Common Stock, issued	23,264,259	23,253,744
Class B Common Stock [Member]
Common Stock, par (in dollars per share)	$ 1	$ 1
Common Stock, authorized	33,000,000	33,000,000
Common Stock, issued	7,925,254	7,935,769
Common Stock, outstanding	7,925,254	7,935,769